An excavator energy recovery and hybrid system

Abstract

The application discloses a kind of excavator energy recovery and hybrid power system, belongs to engineering machinery technical field, fuel power subsystem includes engine, hydraulic pump, main control valve and executing element, engine is connected with hydraulic pump, and hydraulic pump is communicated with each executing element by main control valve;Electric power subsystem includes power battery, second motor, hydraulic pump, main control valve and executing element, power battery is electrically connected with second motor, and second motor is connected with hydraulic pump;Energy recovery subsystem includes energy storage battery, first motor and energy recovery valve, energy recovery valve is connected in the oil circuit between executing element and main control valve, and energy recovery valve is mechanically connected with first motor, and first motor is electrically connected with energy storage battery;Controller is at least with engine, second motor, first motor and energy recovery valve signal connection, solve the existing device structure loose, occupy large space and recovery mode single, difficult to adapt to different operating conditions energy efficiency demand problem.

Description

Technical Field

[0001] This invention relates to an energy recovery and hybrid power system for excavators, belonging to the field of engineering machinery technology. Background Technology

[0002] Currently, excavator energy recovery technologies are mainly divided into two categories: one is hydraulic recovery, which stores the recovered energy through accumulators. However, accumulators are large and heavy, severely restricting the spatial layout of the equipment, and pressure fluctuations during charging and discharging can easily cause hydraulic shocks. Some solutions achieve recovery and reuse through methods such as internal regeneration of the valve core, but this method can only recover energy in a specific direction, and the recovered energy can only be used to power the stick or other specific actuators, without flexible allocation. The other category is electric recovery, which recovers the slewing braking potential energy through electric slewing, or converts hydraulic energy into electrical energy by driving a generator with a hydraulic motor, storing it in batteries or capacitors for use by other electrical components. However, this method involves multiple conversions of hydraulic, mechanical, and electrical energy, resulting in cumulative energy losses and a low overall recovery efficiency.

[0003] However, the existing solutions mentioned above all have the following shortcomings: First, energy recovery devices are usually assembled from independent hydraulic motors, generators and matching valve groups. The components are scattered, resulting in a loose overall structure and a large space occupation, which makes it difficult to meet the requirements of miniaturized and lightweight engineering machinery. Second, existing systems generally only support a single hydraulic recovery mode or a single electric recovery mode, and cannot flexibly select the reuse path of recovered energy according to the working conditions, resulting in insufficient mode adaptability. Summary of the Invention

[0004] The purpose of this invention is to provide an excavator energy recovery and hybrid power system. By integrating a high-speed rotary motor on a first motor to form a compact energy conversion unit, and realizing on-demand switching between hydraulic energy recovery and electric energy recovery, this system solves the problems of existing excavator energy recovery devices having loose structures, large space occupation, single recovery modes, and difficulty in adapting to the energy efficiency requirements of different working conditions.

[0005] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution:

[0006] This invention provides an excavator energy recovery and hybrid power system, comprising:

[0007] Fuel power subsystem, electric power subsystem, energy recovery subsystem, and controller;

[0008] The fuel power subsystem includes an engine, a hydraulic pump, a main control valve, and at least one actuator. The engine is driven to the hydraulic pump, and the hydraulic pump is connected to each actuator through the main control valve. The engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive each actuator to operate.

[0009] The electric power subsystem includes a power battery, a second motor, the hydraulic pump, the main control valve, and at least one actuator. The power battery is electrically connected to the second motor, and the second motor is driven to the hydraulic pump. The second motor is used to drive the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate.

[0010] The energy recovery subsystem includes an energy storage battery, a first motor, and an energy recovery valve. The first motor is an electric motor or generator that integrates a high-speed rotating motor. The energy recovery valve is connected in the oil circuit between each actuator and the main control valve, and the energy recovery valve is also mechanically connected to the first motor. The first motor is electrically connected to the energy storage battery.

[0011] The controller is at least signal-connected to the engine, the second motor, the first motor, and the energy recovery valve.

[0012] Furthermore, the system also includes a first fuel supply mode, a second fuel supply mode, and a third fuel supply mode;

[0013] The first oil supply mode is as follows: the energy storage battery supplies power to the first motor, and the first motor supplies pressurized oil to the main control valve to drive the actuators to operate.

[0014] The second oil supply mode is as follows: the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate;

[0015] The third oil supply mode is as follows: the power battery supplies power to the second motor, and the second motor drives the hydraulic pump to supply pressurized oil to the main control valve to drive the various actuators to operate;

[0016] The energy recovery valve is used to transfer some or all of the hydraulic energy generated by the actuator during operation to the first motor, and the first motor is used to convert the hydraulic energy into electrical energy and store it in the energy storage battery.

[0017] The system is also equipped with a combined fuel supply mode:

[0018] The first fuel supply mode is combined with the second fuel supply mode; and / or,

[0019] The first fuel supply mode is combined with the third fuel supply mode;

[0020] Furthermore, in the combined fuel supply mode, when the first fuel supply mode is combined with the third fuel supply mode, the energy storage battery is used for charging and discharging load to reduce the charging and discharging frequency of the power battery.

[0021] Furthermore, the energy recovery valve is connected to the energy recovery oil circuit of the actuator, and is used to transfer the hydraulic energy generated by the corresponding actuator to the first motor when the actuator is activated. The actuator includes at least a boom cylinder, a stick cylinder, a swing motor and a travel motor.

[0022] The sources of hydraulic energy recovery include at least: the potential energy when the boom descends, the potential energy when the stick retracts, the overflow loss when starting the slewing, the overflow loss when braking the slewing, the overflow loss when starting the travel, and the overflow loss when braking the travel.

[0023] Furthermore, the generator is drive-connected to the engine and electrically connected to the energy storage battery; the engine also charges the energy storage battery through the generator; the energy storage battery is provided with an external charging interface for connecting to an external power source to charge the energy storage battery.

[0024] Furthermore, the controller is signal-connected to the energy storage battery to monitor the current charge level of the energy storage battery;

[0025] Configure the controller as follows:

[0026] When the current charge of the energy storage battery is lower than the preset lower limit A%, the control system only allows the energy storage battery to charge and prohibits it from discharging.

[0027] When the current charge of the energy storage battery reaches the preset upper limit value B%, the control system will only allow the energy storage battery to discharge and stop its charging.

[0028] Where A < B.

[0029] Furthermore, the system is also equipped with a fuel mode; in the fuel mode, the first motor, the second motor and the energy recovery valve stop working, and only the engine drives the hydraulic pump to supply pressurized oil to the main control valve.

[0030] Furthermore, the system also features a dual-engine mode;

[0031] The dual-engine mode includes a power output mode and a charging mode; the power output mode is as follows:

[0032] The first motor, the second motor, or the engine drives the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the actuators to operate; or,

[0033] The first motor and the second motor jointly drive the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the actuators to operate; or,

[0034] The first motor and the engine together drive the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the various actuators to operate;

[0035] Specifically, when the first motor and the second motor drive together, the output power of the first motor is less than the output power of the second motor; when the first motor and the engine drive together, the output power of the first motor is less than the output power of the engine.

[0036] The charging conditions are as follows:

[0037] The engine charges the energy storage battery through the generator, and / or the first motor charges the energy storage battery and / or the power battery.

[0038] Furthermore, the system is also equipped with a plug-in hybrid mode, in which the system charges the energy storage battery through an external power source;

[0039] The plug-in hybrid mode includes:

[0040] The first motor, the second motor, or the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate.

[0041] The first motor and the second motor together drive the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the actuators to operate.

[0042] The first motor and the engine together drive the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the various actuators to operate;

[0043] In addition, the engine charges the energy storage battery through the generator, the first motor charges the energy storage battery, and / or an external power source charges the energy storage battery.

[0044] Furthermore, the system is also equipped with a range-extending mode, in which the second motor stops driving the hydraulic pump;

[0045] The range extension modes include:

[0046] The first motor independently drives the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the actuators to operate.

[0047] The engine independently drives the hydraulic pump to supply pressurized oil to the main control valve to drive the various actuators to operate;

[0048] The first motor and the engine jointly drive the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate, and the output power of the first motor is greater than the output power of the engine;

[0049] Furthermore, the engine charges the energy storage battery through the generator, the first motor charges the energy storage battery, and an external power source charges the energy storage battery.

[0050] Furthermore, the system is equipped with an electric mode. In the electric mode, the first motor, the energy recovery valve, and the generator stop working, and only the power battery supplies power to the second motor. The second motor drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate.

[0051] Furthermore, the system is equipped with a start-up mode or a low-power mode; in the start-up mode or low-power mode, the controller controls the energy storage battery to supply power to the first motor, so as to supply pressurized oil to the main control valve to drive the actuators to operate, while controlling the engine to stop working.

[0052] Furthermore, the system is equipped with a power rapid loading mode; in the power rapid loading mode, the controller controls the energy storage battery to supply power to the first motor and simultaneously controls the engine to drive the hydraulic pump, or controls the energy storage battery to supply power to the first motor and simultaneously controls the power battery to supply power to the second motor, with the first motor and the second motor jointly supplying oil to the main control valve.

[0053] Furthermore, the controller is also configured to:

[0054] When the system is in an idle state, the engine and the second motor are controlled to stop working, and the energy storage battery supplies power to the auxiliary electrical components.

[0055] When the energy storage battery is damaged, the system is controlled to switch to fuel mode, where the engine drives the hydraulic pump to supply oil, or to switch to electric mode, where the power battery supplies power to the second motor, and the second motor drives the hydraulic pump to supply oil.

[0056] Furthermore, the energy recovery valve is an electronically controlled proportional valve, and the controller is signal-connected to the energy recovery valve to adjust the opening degree of the energy recovery valve according to the current charge of the energy storage battery and / or the operating condition of the actuator.

[0057] Furthermore, the controller is also configured to: if the load condition is within a preset low load condition range, control the engine to charge the energy storage battery through the generator.

[0058] Furthermore, the controller is also configured to switch operating modes based on the current charge level of the energy storage battery and the current workload:

[0059] When the energy storage battery has a charge level higher than a preset value, the first fuel supply mode is used.

[0060] When the energy storage battery's charge level is lower than a preset lower limit, the engine is controlled to charge the energy storage battery through the generator, or the system is switched to either fuel mode or electric mode.

[0061] When the power required by the actuator exceeds a preset threshold, the system is controlled to enter the combined oil supply mode.

[0062] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0063] 1. This invention mechanically connects the energy recovery valve to a first motor integrated with a high-speed rotating motor, allowing the hydraulic energy recovered by the actuator to directly drive the first motor to generate electricity and store it in the energy storage battery. This eliminates the need for separate hydraulic motors and generators, reducing system components and overall machine space requirements. It solves the problems of existing excavator energy recovery devices having loose structures, large space requirements, and single recovery modes, making it difficult to adapt to different working conditions and energy efficiency needs.

[0064] 2. By setting a first oil supply mode, a second oil supply mode, a third oil supply mode, and a combination of oil supply modes, the present invention enables the system to select a single or combination of power supply methods from energy storage battery power supply, engine drive, or power battery power supply to supply pressurized oil to the main control valve according to the working conditions, thereby avoiding energy waste caused by a single oil supply path and improving the system's energy utilization efficiency.

[0065] 3. By setting fuel mode, electric mode, dual-engine mode, plug-in hybrid mode and range-extending mode, the present invention enables the system to operate in various working states such as pure fuel drive, pure electric drive, hybrid drive, external charging and range-extending, which meets the power requirements of excavators in different working scenarios and broadens the system's adaptability to different working conditions.

[0066] 4. This invention monitors the current charge level of the energy storage battery through a controller, and only allows charging when the current charge level is below a preset lower limit A% and only allows discharging when it reaches a preset upper limit B%, thus avoiding overcharging or over-discharging of the energy storage battery and extending its service life. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of the structure of an excavator energy recovery and hybrid power system provided in an embodiment of the present invention. Detailed Implementation

[0068] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0069] The term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0070] Example 1

[0071] like Figure 1 As shown in the figure, this embodiment introduces an excavator energy recovery and hybrid power system, including: a fuel power subsystem, an electric power subsystem, an energy recovery subsystem, and a controller (not shown in the figure).

[0072] The fuel-powered subsystem includes an engine, a hydraulic pump, a main control valve, and at least one actuator. The engine is driven by the hydraulic pump, which is connected to each actuator via the main control valve. The engine drives the hydraulic pump to rotate, supplying pressurized oil to the main control valve. The pressurized oil is then distributed by the main control valve and flows into each actuator to drive its operation.

[0073] This embodiment sets up a transmission connection between the engine and the hydraulic pump, and connects the hydraulic pump to each actuator through the main control valve. This allows the engine to directly drive the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators. As a result, the system can still maintain normal operation when the power battery is low or the second motor fails, which helps to improve the reliability of the system.

[0074] The electric power subsystem includes a power battery, a second motor, the hydraulic pump, the main control valve, and at least one actuator. The power battery is electrically connected to the second motor and supplies power to it. The second motor is drively connected to the hydraulic pump, driving the pump to rotate and supply pressurized oil to the main control valve. The pressurized oil is then distributed by the main control valve and flows into each actuator to drive them to operate.

[0075] This embodiment connects the power battery to the second motor and the second motor to the hydraulic pump, enabling the second motor to drive the hydraulic pump to supply pressurized oil to the main control valve to drive the actuator. This allows for pure electric drive when the engine is off or fuel is insufficient, which helps reduce fuel consumption and operating noise.

[0076] The energy recovery subsystem includes a storage battery, a first motor, and an energy recovery valve. The first motor is an electric motor or generator integrated with a high-speed rotating motor; that is, the first motor and the high-speed rotating motor are integrated into a single unit, sharing a housing and rotor shaft. The energy recovery valve is connected to the oil circuit between each actuator and the main control valve, and is also mechanically connected to the first motor. When the actuator is in a passive retraction or gravity-induced descent condition, the pressurized oil discharged from the actuator flows into the first motor through the energy recovery valve, driving the first motor to rotate and generate electricity. The first motor is electrically connected to the storage battery, and the electrical energy generated by the first motor is stored in the storage battery.

[0077] This embodiment connects the energy recovery valve to the oil circuit between each actuator and the main control valve, and mechanically connects the energy recovery valve to the first motor integrated with a high-speed rotating motor. This allows the pressure oil discharged from the actuator to directly drive the first motor to rotate and generate electricity, which is then stored in the energy storage battery. This eliminates the need for separate hydraulic motors and generators, reducing the number of system components and the overall space occupied. At the same time, it avoids energy loss caused by multiple conversions of hydraulic energy, which helps to improve energy recovery efficiency.

[0078] The controller is connected to at least the engine, the second motor, the first motor, and the energy recovery valve via signal connection, and is used to control the speed and torque of the engine, the start-stop and operating status of the second motor and the first motor, and the opening and closing of the energy recovery valve.

[0079] This embodiment connects the controller to at least the engine, the second motor, the first motor, and the energy recovery valve, enabling the controller to control the engine speed and torque, the start-stop and operating status of the second and first motors, and the opening and closing of the energy recovery valve in real time according to the operating conditions. This achieves coordinated operation between the fuel power subsystem, the electric power subsystem, and the energy recovery subsystem, which is beneficial to improving the system response speed and energy management efficiency.

[0080] In this embodiment, the energy recovery valve is mechanically connected to a first motor that integrates a high-speed rotating motor, so that the hydraulic energy recovered by the actuator can directly drive the first motor to generate electricity. This eliminates the need for a separate hydraulic motor and generator, reducing the number of system components and the overall space occupied by the machine.

[0081] Example 2

[0082] Based on the same inventive concept as Embodiment 1, this embodiment introduces an excavator energy recovery and hybrid power system, focusing on the system's working mode and control strategy.

[0083] In this embodiment, the system further includes a first oil supply mode, a second oil supply mode, and a third oil supply mode. The first oil supply mode is as follows: the energy storage battery supplies power to the first motor, and the first motor supplies pressurized oil to the main control valve to drive the actuators. The second oil supply mode is as follows: the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators. The third oil supply mode is as follows: the power battery supplies power to the second motor, and the second motor drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators.

[0084] The energy recovery valve is used to transfer some or all of the hydraulic energy generated by the actuator during operation to the first motor, which then converts the hydraulic energy into electrical energy and stores it in the energy storage battery. Specifically, when the actuator retracts passively or descends due to gravity, the pressure oil discharged from it flows into the first motor through the energy recovery valve, driving the first motor to rotate and generate electricity, which is then stored in the energy storage battery.

[0085] The system also includes a combined oil supply mode: a combination of the first oil supply mode and the second oil supply mode; and / or, a combination of the first oil supply mode and the third oil supply mode. In the combined oil supply mode, when the first oil supply mode and the third oil supply mode are combined, the energy storage battery is used to charge and discharge the load, thereby reducing the charging and discharging frequency of the power battery. For example, when the excavator is under heavy-load excavation conditions, a combination of the first and second oil supply modes is used, meaning the energy storage battery supplies power to the first motor, and simultaneously the engine drives the hydraulic pump, both supplying pressurized oil to the main control valve to meet the high-flow oil supply demand. When the power battery has sufficient charge and oil consumption needs to be reduced, a combination of the first and third oil supply modes is used, meaning the energy storage battery supplies power to the first motor, and simultaneously the power battery supplies power to the second motor, both supplying pressurized oil to the main control valve.

[0086] The energy recovery valves are connected to the energy recovery oil circuits of the actuators, respectively, and are used to transfer the hydraulic energy generated by the actuators to the first motor when the actuators are activated. The actuators include at least a boom cylinder, a stick cylinder, a swing motor, and a travel motor. The sources of the recovered hydraulic energy include at least: the potential energy during boom descent, the potential energy during stick retraction, the overflow loss during swing start, the overflow loss during swing braking, the overflow loss during travel start, and the overflow loss during travel braking. During boom descent, the pressurized oil discharged from the rodless chamber of the boom cylinder flows into the first motor through the energy recovery valves; during swing braking, the pressurized oil discharged from the swing motor flows into the first motor through the energy recovery valves; during travel deceleration, the pressurized oil discharged from the travel motor flows into the first motor through the energy recovery valves.

[0087] In this embodiment, the system further includes a generator, which is connected to the engine via a transmission connection and is also electrically connected to the energy storage battery. The engine also charges the energy storage battery through the generator; that is, during engine operation, it drives the generator to rotate and generate electricity, which is stored in the energy storage battery. The energy storage battery is equipped with an external charging interface for connecting to an external power source to charge the battery, thus enabling the system to have external charging capabilities.

[0088] The controller is connected to the energy storage battery via a signal connection and is used to monitor the current charge level of the energy storage battery. The controller is configured such that: when the current charge level of the energy storage battery is lower than a preset lower limit A%, the system is controlled to only allow the energy storage battery to charge and prohibit its discharge; when the current charge level of the energy storage battery reaches a preset upper limit B%, the system is controlled to only allow the energy storage battery to discharge and stop its charging; where A < B. For example, A is set to 20% and B is set to 90%, meaning that when the energy storage battery charge level is below 20%, discharging is prohibited and only charging is allowed; when the charge level reaches 90%, charging is prohibited and only discharging is allowed, thereby preventing overcharging or over-discharging of the energy storage battery and extending its service life.

[0089] This embodiment enables the system to flexibly select a single or combined oil supply mode according to the working conditions by setting a first oil supply mode, a second oil supply mode, a third oil supply mode, and a combination of oil supply modes, thereby avoiding energy waste caused by a single oil supply path. By monitoring the energy storage battery's power in real time and limiting its charge and discharge, the controller ensures that the energy storage battery operates within a safe power range, thereby improving the system's operational safety and battery life.

[0090] In this embodiment, the first motor is also electrically connected to the power battery. The first motor is configured to selectively supply electrical energy to the energy storage battery and / or the power battery. Specifically, the first motor is connected to the energy storage battery and the power battery respectively via power lines, and a controllable power switching device, such as a contactor or relay, is provided between them. The on / off state of the switching device is controlled by a controller to determine the direction of the power generated by the first motor.

[0091] The controller is further configured to: when the current charge level of the power battery is lower than a preset threshold, and the current charge level of the energy storage battery is higher than a preset allowable discharge lower limit, for example, higher than a stop threshold for the first motor to charge the energy storage battery, control the first motor to deliver the recovered electrical energy to the power battery to charge the power battery. Through this control strategy, when the power battery charge is insufficient, the first motor can convert the recovered hydraulic energy into electrical energy and directly replenish the power battery, avoiding over-discharge of the power battery, extending the power battery's lifespan, and improving the overall energy utilization efficiency of the vehicle.

[0092] Preferably, when the current charge level of the power battery is lower than a first preset threshold and the current charge level of the energy storage battery is higher than a second preset threshold, the controller prioritizes controlling the first motor to charge the power battery; when the current charge level of the power battery is higher than a third preset threshold, the controller controls the first motor to stop charging the power battery to avoid overcharging the power battery. The specific values ​​of the above preset thresholds can be set by those skilled in the art according to the actual battery characteristics and operational requirements, and this embodiment does not impose specific limitations on them.

[0093] Example 3

[0094] Based on the same inventive concept as other embodiments, this embodiment introduces an excavator energy recovery and hybrid power system, focusing on the switching and control of multiple working modes of the system.

[0095] In this embodiment, the system also includes a fuel mode. In this fuel mode, the first motor, the second motor, and the energy recovery valve cease operation; only the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators. This mode is suitable for emergency operation scenarios when both the energy storage battery and the power battery are low on power, or when an electrical fault occurs in the system.

[0096] The system also includes an electric mode. In this mode, the first motor, the energy recovery valve, and the generator cease operation, and the power battery supplies power only to the second motor. The second motor drives the hydraulic pump to supply pressurized oil to the main control valve, thereby actuating the various actuators. This mode is suitable for pure electric operation scenarios where the engine is off and the energy storage battery is low on charge, but the power battery has sufficient charge.

[0097] The system also features a dual-engine mode. This dual-engine mode includes a power output mode and a charging mode. The power output mode is as follows: the first motor, the second motor, or the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators; or, the first motor and the second motor jointly drive the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators; or, the first motor and the engine jointly drive the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators. When the first motor and the second motor jointly drive the system, the output power of the first motor is less than that of the second motor; when the first motor and the engine jointly drive the system, the output power of the first motor is less than that of the engine. The charging mode is as follows: the engine charges the energy storage battery through the generator, and / or, the first motor charges the energy storage battery and / or charges the power battery. In this dual-engine mode, the system does not charge the energy storage battery through an external power source; all charging energy comes from the hydraulic energy recovered by the engine or actuators.

[0098] The system also includes a plug-in hybrid mode. In this mode, the system charges the energy storage battery via an external power source. The plug-in hybrid mode includes: the first motor, the second motor, or the engine driving the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators; the first motor and the second motor jointly driving the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators; the first motor and the engine jointly driving the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators; and the engine charging the energy storage battery via the generator, the first motor charging the energy storage battery, and / or, the external power source charging the energy storage battery. In plug-in hybrid mode, the external power source can serve as the primary charging source, working in conjunction with internal power generation and recycling to maintain the energy storage battery's charge balance.

[0099] The system also includes a range-extending mode. In this mode, the second motor stops driving the hydraulic pump. The range-extending mode includes: the first motor independently driving the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators; the engine independently driving the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators; the first motor and the engine jointly driving the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators, with the first motor's output power exceeding the engine's output power; and the engine charging the energy storage battery via the generator, the first motor charging the energy storage battery, and an external power source charging the energy storage battery. In range-extending mode, the second motor is deactivated, with the first motor serving as the primary electric power source and the engine as an auxiliary power source and range-extending charging source, suitable for operational scenarios where the second motor fails or where extended driving range is required.

[0100] The switching between the above modes is automatically executed by the controller based on the energy storage battery power, power battery power, operating load, and operating instructions, or manually selected by the operator. Specifically, when the energy storage battery power is higher than a preset value, the controller prioritizes the first motor to participate in the drive; when the energy storage battery power is lower than a preset value, the controller prioritizes controlling the engine to charge the energy storage battery through the generator, or controls the system to switch to fuel mode or electric mode.

[0101] This embodiment enables the system to operate in various working states, including pure fuel drive, pure electric drive, hybrid drive, external charging, and range-extended driving, by setting fuel mode, electric mode, dual-engine mode, plug-in hybrid mode, and range-extended mode. This meets the power requirements of excavators in different operating scenarios and broadens the system's adaptability to different working conditions. At the same time, the controller can automatically or manually switch between modes, which is beneficial to adjust the power output strategy in real time according to the actual working conditions and improve the overall energy efficiency of the system.

[0102] Example 4

[0103] Based on the same inventive concept as other embodiments, this embodiment introduces an excavator energy recovery and hybrid power system, focusing on the system's fuel supply mode control and energy recovery control strategy.

[0104] In this embodiment, the system includes a first oil supply mode, a second oil supply mode, and a third oil supply mode. The first oil supply mode is as follows: the energy storage battery supplies power to the first motor, and the first motor supplies pressurized oil to the main control valve to drive the actuators. The second oil supply mode is as follows: the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators. The third oil supply mode is as follows: the power battery supplies power to the second motor, and the second motor drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators.

[0105] The controller selects the appropriate oil supply mode based on the current operating conditions and energy status. Specifically, when the flow rate required by the actuator is less than a first preset threshold, the controller selects the first oil supply mode, where the first motor, powered by the energy storage battery, supplies oil independently. When the flow rate required by the actuator is greater than a second preset threshold, the controller selects a combined oil supply mode, i.e., a combination of the first and second oil supply modes, or a combination of the first and third oil supply modes, where two power sources jointly supply pressurized oil to the main control valve to meet the high flow rate requirement. The system also includes a combined oil supply mode: a combination of the first and second oil supply modes; and / or, a combination of the first and third oil supply modes.

[0106] The energy recovery valves are connected to the energy recovery oil circuits of the actuators, respectively, and are used to transmit the hydraulic energy generated by the actuators to the first motor when the actuators are activated. The actuators include at least a boom cylinder, a stick cylinder, a swing motor, and a travel motor. Specifically:

[0107] When the boom descends, the pressure oil in the rodless chamber of the boom cylinder is discharged under the action of gravity. The discharged pressure oil flows into the first motor through the energy recovery valve, driving the first motor to rotate. The first motor converts mechanical energy into electrical energy and stores it in the energy storage battery. At the same time, the discharged pressure oil generates back pressure after being throttled by the energy recovery valve, so that the boom descends smoothly at a controllable speed.

[0108] When the slewing brake is applied, the slewing motor continues to rotate under inertia, and the pressure oil discharged from it flows into the first motor through the energy recovery valve, driving the first motor to rotate and generate electricity. At the same time, the generating torque of the first motor is used to apply braking torque to the slewing mechanism to realize braking energy recovery.

[0109] When the walking speed decreases, the walking motor continues to rotate under inertia, and the pressure oil discharged by it flows into the first motor through the energy recovery valve, driving the first motor to rotate and generate electricity, thereby realizing the recovery of walking braking energy.

[0110] The energy recovery valve is an electrically controlled proportional valve, and its opening degree is adjusted in real time by the controller according to the operating conditions of the actuator and the current charge of the energy storage battery. When the current charge of the energy storage battery is lower than the preset lower limit A%, the controller controls the energy recovery valve to open to the maximum opening degree, so that as much of the pressurized oil discharged from the actuator as possible flows into the first motor for power generation; when the current charge of the energy storage battery reaches the preset upper limit B%, the controller controls the energy recovery valve to close or reduce its opening degree, stopping or reducing the charging of the energy storage battery.

[0111] In this embodiment, the system further includes a generator, which is connected to the engine via a transmission connection and is also electrically connected to the energy storage battery. The engine charges the energy storage battery through the generator; that is, during engine operation, the engine drives the generator to rotate, and the electrical energy generated by the generator is rectified and stored in the energy storage battery. The energy storage battery is also provided with an external charging interface for connecting to an external power source to charge the energy storage battery, thus enabling the system to have external charging capability.

[0112] This embodiment connects the energy recovery valve to the energy recovery oil circuit of each actuator, enabling the hydraulic energy under different working conditions such as boom descent, swing braking, and travel deceleration to be recovered and used to generate electricity for the first motor, thus broadening the energy recovery range. The controller adjusts the opening of the energy recovery valve in real time according to the battery charge, avoiding overcharging of the battery and improving the system's operational safety. By combining the first, second, and third oil supply modes, the system can flexibly match the oil supply mode according to the flow requirements of the actuators, avoiding the problem of insufficient oil supply or energy waste from a single power source.

[0113] Example 5

[0114] Based on the same inventive concept as other embodiments, this embodiment introduces an excavator energy recovery and hybrid power system, and further illustrates the control strategy of the system under various working conditions.

[0115] The system has a start-up or low-power mode. In the start-up or low-power mode, the controller controls the energy storage battery to supply power to the first motor, which drives the hydraulic pump to supply pressurized oil to the main control valve to drive the various actuators; simultaneously, the controller controls the engine to stop working. This control strategy avoids the engine operating in a low-fuel-consumption range, solves the problem of speed drop and stalling caused by slow engine transient response, and improves the overall machine response time.

[0116] The system features a rapid power loading mode. In this mode, the controller controls the energy storage battery to supply power to the first motor and simultaneously controls the engine to drive the hydraulic pump. The first motor and the engine jointly supply pressurized oil to the main control valve to drive the various actuators. Alternatively, the controller controls the energy storage battery to supply power to the first motor and simultaneously controls the power battery to supply power to the second motor. The first motor and the second motor jointly supply pressurized oil to the main control valve to drive the various actuators. Through this control strategy, simultaneous oil supply from two power sources is achieved during transient over-power loading, providing strong instantaneous torque and ensuring power response.

[0117] The controller is also configured to: when the system is in idle state, control the engine and the second motor to stop working, and supply power to the auxiliary electrical components by the energy storage battery; thereby achieving zero fuel consumption and zero emissions. When the energy storage battery fails, control the system to switch to fuel mode, where the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators; or switch to electric mode, where the power battery supplies power to the second motor, and the second motor drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators. Through the above redundancy backup strategy, the system can still maintain basic operating capabilities when the energy storage battery fails, improving system reliability.

[0118] The energy recovery valve is an electronically controlled proportional valve. The controller is signal-connected to the energy recovery valve and is used to adjust the opening of the energy recovery valve according to the current charge level of the energy storage battery and / or the operating condition of the actuator. Specifically, when the current charge level of the energy storage battery is lower than a preset lower limit, the controller controls the energy recovery valve to open to a larger degree, allowing as much pressurized oil discharged from the actuator as possible to flow into the first motor for power generation. When the current charge level of the energy storage battery reaches a preset upper limit, the controller controls the energy recovery valve to reduce its opening or close, stopping or reducing the charging of the energy storage battery. Through the above redundancy backup strategy, the system can still maintain basic operating capabilities in the event of a battery failure, improving system reliability.

[0119] The controller is also configured to: if the load condition is within a preset low load range, control the engine to charge the energy storage battery through the generator. This allows for charging using the engine's reserve capacity during low-load operation, improving energy utilization efficiency.

[0120] The controller is also configured to switch operating modes based on the current charge level of the energy storage battery and the current workload: when the charge level of the energy storage battery is higher than a preset value, the first fuel supply mode is adopted, i.e., the energy storage battery supplies power to the first motor, and the first motor supplies pressurized oil to the main control valve; when the charge level of the energy storage battery is lower than a preset lower limit, the engine is controlled to charge the energy storage battery through the generator, or switch to the fuel mode or the electric mode; when the power required by the actuator is greater than a preset threshold, the system is controlled to enter the combined fuel supply mode. Through the above control strategy, the optimal fuel supply mode is automatically matched according to the real-time status of the charge level and load, thereby improving the overall energy efficiency of the system.

[0121] In summary, the present invention mechanically connects the energy recovery valve to a first motor integrated with a high-speed rotating motor, allowing the hydraulic energy recovered by the actuator to directly drive the first motor to generate electricity and store it in the energy storage battery. This eliminates the need for a separate hydraulic motor and generator, reduces the number of system components, and lowers the overall machine footprint. It also solves the problems of existing excavator energy recovery devices having a loose structure, large footprint, single recovery mode, and difficulty in adapting to the energy efficiency requirements of different working conditions.

[0122] This invention enables the system to select a single or combined method of supplying pressurized oil to the main control valve based on the operating conditions, by setting a first oil supply mode, a second oil supply mode, a third oil supply mode, and a combination of oil supply modes. This avoids energy waste caused by a single oil supply path and improves the system's energy utilization efficiency.

[0123] This invention enables the system to operate in various working states, including pure fuel drive, pure electric drive, hybrid drive, external charging, and range-extending, by setting fuel mode, electric mode, dual-engine mode, plug-in hybrid mode, and range-extending mode. This meets the power requirements of excavators in different operating scenarios and broadens the system's adaptability to various working conditions.

[0124] This invention monitors the current charge level of the energy storage battery through a controller, and only allows charging when the current charge level is below a preset lower limit A% and only allows discharging when it reaches a preset upper limit B%, thus avoiding overcharging or over-discharging of the energy storage battery and extending its service life.

[0125] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. An excavator energy recovery and hybrid power system, characterized in that, include: Fuel power subsystem, electric power subsystem, energy recovery subsystem, and controller; The fuel power subsystem includes an engine, a hydraulic pump, a main control valve, and at least one actuator. The engine is driven to the hydraulic pump, and the hydraulic pump is connected to each actuator through the main control valve. The engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive each actuator to operate. The electric power subsystem includes a power battery, a second motor, the hydraulic pump, the main control valve, and at least one actuator. The power battery is electrically connected to the second motor, and the second motor is driven to the hydraulic pump. The second motor is used to drive the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate. The energy recovery subsystem includes an energy storage battery, a first motor, and an energy recovery valve. The first motor is an electric motor or generator that integrates a high-speed rotating motor. The energy recovery valve is connected in the oil circuit between each actuator and the main control valve, and the energy recovery valve is also mechanically connected to the first motor. The first motor is electrically connected to the energy storage battery. The controller is at least signal-connected to the engine, the second motor, the first motor, and the energy recovery valve.

2. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The system also includes a first fuel supply mode, a second fuel supply mode, and a third fuel supply mode; The first oil supply mode is as follows: the energy storage battery supplies power to the first motor, and the first motor supplies pressurized oil to the main control valve to drive the actuators to operate. The second oil supply mode is as follows: the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate; The third oil supply mode is as follows: the power battery supplies power to the second motor, and the second motor drives the hydraulic pump to supply pressurized oil to the main control valve to drive the various actuators to operate; The energy recovery valve is used to transfer some or all of the hydraulic energy generated by the actuator during operation to the first motor, and the first motor is used to convert the hydraulic energy into electrical energy and store it in the energy storage battery. The system is also equipped with a combined fuel supply mode: The first fuel supply mode is combined with the second fuel supply mode; and / or, The first fuel supply mode is combined with the third fuel supply mode; Furthermore, in the combined fuel supply mode, when the first fuel supply mode is combined with the third fuel supply mode, the energy storage battery is used for charging and discharging load to reduce the charging and discharging frequency of the power battery.

3. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The energy recovery valves are connected to the energy recovery oil circuits of the actuators respectively, and are used to transmit the hydraulic energy generated by the actuators to the first motor when the actuators are activated. The actuators include at least a boom cylinder, a stick cylinder, a swing motor and a travel motor. The sources of hydraulic energy recovery include at least: the potential energy when the boom descends, the potential energy when the stick retracts, the overflow loss when starting the slewing, the overflow loss when braking the slewing, the overflow loss when starting the travel, and the overflow loss when braking the travel.

4. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The generator is connected to the engine via a transmission, and the generator is also electrically connected to the energy storage battery. The engine also charges the energy storage battery through the generator. The energy storage battery is provided with an external charging interface for connecting to an external power source to charge the energy storage battery.

5. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The controller is connected to the energy storage battery via a signal and is used to monitor the current charge level of the energy storage battery. Configure the controller as follows: When the current charge of the energy storage battery is lower than the preset lower limit A%, the control system only allows the energy storage battery to charge and prohibits it from discharging. When the current charge of the energy storage battery reaches the preset upper limit value B%, the control system will only allow the energy storage battery to discharge and stop its charging. Where A < B.

6. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The system also has a fuel mode; in the fuel mode, the first motor, the second motor and the energy recovery valve stop working, and only the engine drives the hydraulic pump to supply pressurized oil to the main control valve.

7. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The system is also equipped with a dual-engine mode; The dual-engine mode includes a power output mode and a charging mode; the power output mode is as follows: The first motor, the second motor, or the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate. or, The first motor and the second motor together drive the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the actuators to operate. or, The first motor and the engine together drive the hydraulic pump to supply pressurized oil to the main control valve, so as to drive the various actuators to operate; Specifically, when the first motor and the second motor drive together, the output power of the first motor is less than the output power of the second motor; when the first motor and the engine drive together, the output power of the first motor is less than the output power of the engine; the charging condition is as follows: The engine charges the energy storage battery through the generator, and / or the first motor charges the energy storage battery and / or the power battery.

8. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The system is also equipped with a plug-in hybrid mode, in which the system charges the energy storage battery through an external power source. The plug-in hybrid mode includes: The first motor, the second motor, or the engine drives the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate. The first motor and the second motor together drive the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the actuators to operate. The first motor and the engine together drive the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the various actuators to operate; In addition, the engine charges the energy storage battery through the generator, the first motor charges the energy storage battery, and / or an external power source charges the energy storage battery.

9. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The system is also equipped with a range-extending mode, in which the second motor stops driving the hydraulic pump; The range extension modes include: The first motor independently drives the hydraulic pump to supply pressurized oil to the main control valve, thereby driving the actuators to operate. The engine independently drives the hydraulic pump to supply pressurized oil to the main control valve to drive the various actuators to operate; The first motor and the engine jointly drive the hydraulic pump to supply pressurized oil to the main control valve to drive the actuators to operate, and the output power of the first motor is greater than the output power of the engine; Furthermore, the engine charges the energy storage battery through the generator, the first motor charges the energy storage battery, and an external power source charges the energy storage battery.

10. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The system is equipped with an electric mode. In the electric mode, the first motor, the energy recovery valve, and the generator stop working, and only the power battery supplies power to the second motor. The second motor drives the hydraulic pump to supply pressurized oil to the main control valve to drive the various actuators to operate.

11. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The system is equipped with a start-up mode or a low-power mode; in the start-up mode or low-power mode, the controller controls the energy storage battery to supply power to the first motor, so as to supply pressurized oil to the main control valve to drive the actuators to operate, while controlling the engine to stop working.

12. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The system is equipped with a power rapid loading mode; in the power rapid loading mode, the controller controls the energy storage battery to supply power to the first motor and simultaneously controls the engine to drive the hydraulic pump, or controls the energy storage battery to supply power to the first motor and simultaneously controls the power battery to supply power to the second motor, with the first motor and the second motor jointly supplying oil to the main control valve.

13. The excavator energy recovery and hybrid power system according to claim 1, characterized in that, The controller is also configured to: When the system is in an idle state, the engine and the second motor are controlled to stop working, and the energy storage battery supplies power to the auxiliary electrical components. When the energy storage battery is damaged, the system is controlled to switch to fuel mode, where the engine drives the hydraulic pump to supply oil, or to switch to electric mode, where the power battery supplies power to the second motor, and the second motor drives the hydraulic pump to supply oil.

14. The excavator energy recovery and hybrid power system according to claim 3, characterized in that, The energy recovery valve is an electronically controlled proportional valve. The controller is signal-connected to the energy recovery valve and is used to adjust the opening degree of the energy recovery valve according to the current charge of the energy storage battery and / or the operating condition of the actuator.

15. The excavator energy recovery and hybrid power system according to claim 4, characterized in that, The controller is also configured to: if the load condition is within a preset low load condition range, control the engine to charge the energy storage battery through the generator.

16. The excavator energy recovery and hybrid power system according to claim 2, characterized in that, The controller is also configured to switch operating modes based on the current charge level of the energy storage battery and the current workload: When the energy storage battery has a charge level higher than a preset value, the first fuel supply mode is used. When the energy storage battery's charge level is lower than a preset lower limit, the engine is controlled to charge the energy storage battery through the generator, or the system is switched to either fuel mode or electric mode. When the power required by the actuator exceeds a preset threshold, the system is controlled to enter the combined oil supply mode.

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